Grist, the Hunger Tide

饥潮格蕊斯 (Grist, the Hunger Tide) (zhs)

Legendary Planeswalker - Grist | Loyalty: 3 (CMC 3)
As long as Grist, the Hunger Tide isn't on the battlefield, it's a 1/1 Insect creature in addition to its other types.
+1: Create a 1/1 black and green Insect creature token, then mill a card. If an Insect card was milled this way, put a loyalty counter on Grist and repeat this process.
-2: You may sacrifice a creature. When you do, destroy target creature or planeswalker.
-5: Each opponent loses life equal to the number of creature cards in your graveyard.